LAB NO 2: DIGITAL PROCESSING OF CONTINUOUS SIGNALS

SAMPLING OF CONTINUOUS TIME SIGNALS USING MATLAB™

Source Code:

clf;

t=0:0.00005:1;

f=13;

xa=cos (2*pi*f*t);

subplot (2,1,1);

plot ( t,xa);

grid;

xlabel ('time,msec');

title ('continuous time signal x(at)');

axis ([0 1 -1.2 1.2]);

subplot (2,1,2);

T=0.1;

N=0:T:1;

xs=cos (2*pi*f*n);

k=0:length(n)-1;

stem (k,xs);

grid;

xlabel ('Time Index n');

ylabel ('amplitude');

title ('discrete time signalx[n]');

axis ([0 length(n)-1 -1.2 1.2]);

Outputs:

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

-1

-0.5

0

0.5

1

time,msec

continuous time signal x(at)

0 5 10 15 20 25 30 35 40

-1

-0.5

0

0.5

1

Time Index n

ampl

itude

discrete time signalx[n]

THE ALIASING EFFECT Source Code:

t=0:0.0005:1;

f=13;

Ya=cos (2*pi*f*t);

subplot(2,1,1);

plot(t,Ya);grid;

xlabel('time, msec');

ylabel('Amplitude');

Axis([0 1 -1.2 1.2]);

subplot(2,1,2);

T=0.1;f=13;

N=(0:T:1);

Ys=cos(2*pi*f*n);

T=linespace(-0.5,1.5,500);

TYa=sinc((1/T)*t(:,ones(size(n)))-(1/T)*n(:,ones(size(t)))*Ys;

plot(n,Ys,'o',t,Tya);

grid;

xlabel('Time,msec');

Ylabel('Amplitude');

axis([0 1 -1.2 1.2]);

THE QUANTIZATION PROCESS

Source Code:

% in quantization process we have to determine binary equivalent of our

% decimal number only

d=input('please type in decimal fraction=');

b=input('type in desired wordlength=');

d1=abs(d);

beq=[zeros(1,b)];

for k=1:b;

int=fix((2*dl));

beq(k)=int;

d1=2*d1-int;

end

if sign(d)==-1;

bin=[1 beq];

else

bin=[0 beq];

end

disp('the binary equivalent is');

disp(bin);

Matlab Results:

please type in decimal fraction=3

type in desired word length=4

the binary equivalent is 0011